The subject invention generally relates to a drive axle assembly including a pumping mechanism for maintaining a dual fluid level within the axle assembly. More specifically, the subject invention utilizes the pumping mechanism to maintain a first fluid level within an axle housing and a second, higher, fluid level within a wheel end gear housing.
Many drive axle assemblies utilize gear sets at wheel ends to increase torque output. The gear sets are driven by axle shafts that receive driving input torque from a center differential gear assembly. The axle shafts and center differential gear assembly are enclosed within an axle housing and the wheel end gear sets are enclosed within gear housings mounted to opposing ends of the axle housing.
In order for the center differential gear assembly and the wheel end gear sets to operate smoothly and efficiently, proper lubrication should be maintained. Traditionally, the axle assembly is filled with a lubrication fluid until both the axle housing and gear housing are filled to sufficient lubrication levels. This requires a significant amount of lubricating fluid. Further, the axle housing can be overfilled with fluid in order to achieve the desired fluid levels in the gear housings. This can decrease the overall operating efficiency of the drive axle assembly.
There is a need for a drive axle assembly that can maintain different fluid levels in axle and wheel end gear housings in order to reduce the amount of lubricating fluid needed, in addition to overcoming the other above-mentioned deficiencies in the prior art.